Clamp



y 3, 1966 w. A. SMITH 3,249,351

CLAMP Filed Dec. 26, 1961 2 Sheets-Sheet l INVENTOR. Wilfred A. Smithgym/m W. A. SMITH May 3, 1966 CLAMP 2 Sheets-Sheet 2 Filed Dec. 26. 1961Fig.4b

INVENTOR. Wilfred A. Smith United States Patent 3,249,351 CLAMP WilfredA. Smith, La Honda, Calif. (1102 Vera Ave., Redwood City, Calif.) FiledDec. 26, 1961, Ser. No. 161,978 4 Claims. (Cl. 269-236) This inventionrelates to a clamping device and more particularly to a cam operatedclamp.

- Cam operated clamps have long been used in'a variety of applications.In most cases these prior art cam operated clamps in tightening the jawsof the clamp put an unusually high shearing force on the pin or othersupport member for the movable part of the clamp. Inasmuch as thepivotal supports for the clamp ja-w that is moved to clamp an articlebetween the jaws of the clamp is ordinarily a rather light weight andsmall diameter member, in many cases the shear forcesare sufficientlygreat to break the pivotal support. Efforts to strengthen this point ofweakness have not in the past been entirely saitsfactory because inenlarging the cross sectional area of the member the resulting clamp isbulky, unduly clumsy and in many cases hard to operate.

The present invention overcomes these deficiencies in prior art camoperating clamps by eliminating the use of the pivotal support member asa stress bearing member during and after the clamp is closed. Basicallythe present invention includes a pivotally supported jaw on one end .ofthe clamp and a cam lever cooperating therewith which acts to move thejaw closer to the fixed or opposite end of the clamp by hearing againstcam surfaces on the frame of the clamp and on the movable jaw so that,as a result, the forces exerted on the frame of the clamp act directlythrough the cam rather than by way of the pivotal jaw support.

Therefore, the principal object of this invention is to provide a ca mactuated clamp wherein the support member for the movable jaw is notplaced under stress as the clamp is closed.

Another object of the invention is to provide a cam actuated clamphaving the above described characteristics which is economical tomanufacture and simple to use.

Features of the invention generally pertain to various embodiments bywhich the principle of camming the movable jaw into a closed positionbetween the jaw or the work piece and the frame itself is operative,which operation avoids stressing the member that pivotally connects themovable jaw and theframe of the clamp.

In one feature of the invention, the movable jaw is a I flat platepivotally supported with two degrees of freedom in :a pair of verticalslots at one end of the clamp frame in such a way that the cam carriedby the lever or operating arm acts to move the jaw plate away from theframe and toward the other jaw as the clamp is closed.

In another exemplary embodiment of the invention, the lever is loosely,pivotally supported at one end of the frame and the cam carried by itacts to pull the clamp tight by forcing the frame outwardly away fromone side of the work surface of the board or other member to be clampedbetween the jaws of the clamp as the fixed jaw grips the opposite sideof the work piece. That is to say, the lever and cam carried by it actas the movable jaw so that a finm grip on a piece of lumber or othermaterial is obtained without having a separate jaw and lever as is thecase in the first mentioned embodiment.

These and other objects, advantages and features of the invention may bemore clearly understood when the following detailed description is readwith reference to the drawings, in which:

'FIG. 1 is an end elevational view of one embodiment of the clamp takenshbstantially on line 1-1 of FIG. 3

3,249,351 Patented May 3, 1966 FIG. 2a is a side view of a firstembodiment of the I present invention with the clamp in the openposition;

FIG. 2b is a side view of the first embodiment of the present inventionwith the clamp in the closed position;

FIG. 3 is a plan view of the first embodiment of the invention of FIGS.2a and 2b;

FIG. 4a is a side view of a second embodiment of the present inventionwith the clamp in the open position;

FIG. 4b is a side view of a second embodiment of the present inventionwith the clamp in the closed position; and

FIG. 5 is a plan view of the second embodiment of the invention of FIGS.4a and 4b.

For purposes of convenience and clarity of understanding the use of thepresent clamp will be described in particular reference to the clampingof wood members, particularly for example 2 x 4s, as they may be used inthe construction of concrete pouring forms and the like. Thus, forexample, the embodiment of the clamp of FIGS. 1-3 is shown in referenceto clamping pairs of 2 x 4s 10 in spaced parallel arrangement as may bedesirable to do in clamping horizontal 2 x 4'5, known as Whalers,exteriorly of concrete form structures (not shown). However, it isunderstood that the scope of the invention is in no way limited to anyparticular use or uses to which it may be put, and obviously, many otheruses for a clamp embodying the invention can be envisioned. I

The first embodiment of the invention, 11 is illustrated in detail inFIGS. 2 and 3. The clamp includes a C-shaped frame 21 having an elongateleg 22 on its lower end and a transverse cross piece 23 welded orotherwise affixed to its end and lying in a plane transverse to theplane of leg 22. The other end of the frame 21 has a shoulder 24, with acircular aperture 25 formed therein. The lever 26 carrying a cam 27 ispivotally supported through apertures 25 by a pin 28, the diameter ofwhich is smaller than the apertures 25. This assures a loose fit betweenthe pin 28 and the sides defining the apertures 25 which leaves alimited t-wo degree of freedom structure in respect to lever 26 andintegral cam 27, i.e. there may occur rotational movement and a limitedamount of movement due to the diameter of pin 28, which carries lever 26and cam 27, being less than the diameter of the supporting apertures 25.

In order to close the clamp illustrated in FIGS. 2 and 3, the lever 26is moved downwardly in the direction of the arrow to the positionillustrated in FIG. 2b and the cam 27 bears against the inside surface29 of the frame 21 and against the top part of the clamped member 31illustrated by dotted lines in the FIGS. 2a and 212. It will be notedthat the upper part 32 of the cam 27 is formed to cooperate withinterior surfaces 29 of the frame so as to not only cam against thatsurface as its lower end or movable jaw portion 33 cams against theupper surface of the work piece 31 but it also provides a lockingfunction (particularly seen in FIG. 2b) after the lever 26 is fullyclosed. Furthermore, the lever 26 rests against the work member 31 inthe closed position to stabilize the clamp and work pieces with which itcooperates.

More particularly, as can be seen in FIG. 3, in order to utilize theclamp 11 forming the first embodiment of the present invention, thetransverse member 23 attached to the outward free end of leg 22 isdisposed between a pair of 2 x 4s, for example, and at right angles tothe longitudinal axes with the upright part 21a of the frame 21 lying inbetween the 2 x 4s. The width of the cam surfaces 27 associated with thelever 26 are sufficiently great to bear against the top parts of the2x4s 31 thereby providing a firm connection between the parts. Beyondproviding this clamping action, the thickness of the upright leg 21a maybe varied to provide a predetermined spacing between the members.

It will be observed from FIG. 2b particularly, that when the clamp 11 isclosed, the pin 28is not under any stress but is disposed loosely in theapertures 25. As a result of this construction, the pin 28 may berelatively light without affecting the ruggedness of the clamp itself.The p n acts as a retaining member, not a load bearing one.

Turning to the second embodiment of the present invention (illustratedin FIGS. 4 and 5), though the structure is somewhat different the basicoperating principle is the same. The second embodiment clamp 12 includesa C-shaped frame 41 having a fixed jaw 4-2 attached to the lower leg ofthe C and a movable jaw pivotally supported adjacent the other leg ofthe C-shaped frame 41. More particularly, the movable jaw 43 has a pin44 fixedly attached through it and oriented at right angle to the planeof the frame 41. The upper leg 45 of the frame 41 comprises a bifurcatedfork having vertical slots 46 formed in the tines 47 of the fork. Thepin 44 resides in the slots 46 and permits the jaw 43 to move with twodegrees of freedom. The lever 48 has a transverse cam member 49 affixedto its lower end which lies under upper leg 45 and upon rotation, asillustrated .by the arrow, cams the movable jaw 43 away from the upperleg 45 (see FIG. 4b).

As the movable jaw 43 is cammed downwardly against the work piece 41(shown by dotted lines), the pivotal support pin 44 rides downwardly inthe slots 46, though even after the clamping action is effected asillustrated in FIG. 4b the .pin 44 is loosely disposed in the slots 46.Here again the pin 44 may be relatively light since the camming actiontakes place between the jaw 43 and the interior side 51 of the upper leg45 of the frame 41.

While thev foregoing invention has been described with respect to twoexemplary embodiments, it should be apparent to those skilled in the artthat other changes and variations in the basic concept can be effectedwithout departing from the spirit and scope of the invention. For thisreason the invention should only 'be limited to the extent of theclaims.

What is claimed is:

1. A cam actuated clamp to hold boards, braces and the like togethercomprising, in combination, a C frame having a camming surface on oneend, a movable jaw portion mounted at said one end of C frame, a leverpivotally supported at said one end of C frame and having a cam formedthereon for cooperative engagement with said camming surface and urgingsaid movable jaw to its clamping position, pin means operable to pivotsaid lever thereby forcing and holding said cooperative engagement withsaid camming surface and placing said movable jaw in its clampingposition without stressing the pivotal support for said lever.

2. A cam actuated clamp in accordance with claim 1 wherein said movablejaw portion and cam are integral parts of said lever.

3. A cam actuated clamp in accordance with claim 1 wherein said movablejaw portion is a pivotally supported member and said cam has two camsurfaces which act to increase the spacing between said frame and saidmember to thereby reduce the opening between the jaws of the clamp asthe lever is .moved to a closed position. i

4. A cam actuated clamp comprising, in combination, a C frame having ajaw on one leg and a camming surface on the other leg, a movable ,jawpivotally supported on said other leg for movement with at least onedegree of freedom, and a lever pivotally supported on said frame andhaving a cam formed on one end operable to engage said cam surface andforce said movable jaw away from the frame. while preventing said jawpivotal support from assuming any sensible part of the load.

References Cited by the Examiner UNITED STATES PATENTS 502,533 8/1893Scales 269231 X 630,900 8/1899 Kohl 269 231 X 990,517 4/1911 Blodgett269-231 1,603,191 10/1926 Camblin 269-231 X 2,925,109 2/1960 Walker269236 X FOREIGN PATENTS 979,161 12/1950 France. 726,000 10/ 1942Germany.

WILLIAM W. DYER,'JR., Primary Examiner.

THOMAS J. HICKEY, Examiner.

FREDERICK R. HANDREN, Assistant Examiner. 1

1. A CAM ACTUATED CLAMP TO HOLD BOARDS, BRACES AND THE LIKE TOGETHERCOMPRISING, IN COMBINATION, A C FRAME HAVING A CAMMING SURFACE ON ONEEND, A MOVABLE JAW PORTION MOUNTED AT SAID ONE END OF C FRAME, A LEVERPIVOTALLY SUPPORTED AT SAID ONE END OF C FRAME AND HAVING A CAM FORMEDTHEREON FOR COOPERATIVE ENGAGEMENT WITH SAID CAMMING SURFACE AND URGINGSAID MOVABLE JAW TO ITS CLAMPING POSITION, PIN MEANS OPERABLE TO PIVOTSAID LEVER THEREBY FORCING AND HOLDING SAID COOPERATIVE ENGAGEMENT WITHSAID CAMMING SURFACE AND PLACING SAID MOVABLE JAW IN ITS CLAMPINGPOSITION WITHOUT STRESSING THE PIVOTAL SUPPORT FOR SAID LEVER.